1. Field of the Invention
The invention relates to underground storage tanks generally, and more particularly to a deadman useful for anchoring an underground storage tank to prevent flotation and a method for shipping the deadman alongside a tank.
2. Discussion of the Background
Underground storage tanks (USTs) are commonly used for the storage of liquids, including gasoline, other petroleum products, and wastewater. These tanks are generally cylindrical in shape, with either curved (e.g., hemispherical) or flat ends. Underground storage tanks may be made of many materials, including steel and fiber reinforced plastic (referred to herein as FRP and fiberglass). Such tanks may be single or multi-walled. Such tanks often include ribs, which may be internal or external.
USTs are installed in a wide variety of locations and under a wide variety of conditions. In some locations, the water table is high enough such that some or all of the UST is below the water table. In these situations, a upward buoyant force will act on the tank. If the buoyant force exceeds the downward forces acting on the tank, the tank will xe2x80x98floatxe2x80x99 up out of the ground (referred to herein as flotation). This situation is obviously undesirable.
One method commonly used to ensure that flotation does not occur is through the use of deadmen. Deadmen function as anchors to prevent flotation of the tank. Deadmen are typically installed in pairs with one deadman on each side of and in the plane of the bottom of the tank and are typically constructed of reinforced concrete. Deadmen are typically rectangular in shape and are typically 12 to 36 inches wide, 8 to 12 inches high, and usually have lengths equal to or greater than the corresponding tank. A detailed discussion of deadmen and their use in anchoring underground storage tanks can be found in co-pending U.S. application Ser. No. 09/657,807, filed on Sep. 8, 2000, entitled xe2x80x9cUnderground Storage Tank Buoyancy and Buoyancy Safety Factor Calculation Method and Apparatus,xe2x80x9d which is commonly owned by the assignee of the present application and which is hereby incorporated by reference herein.
Tanks are commonly attached to deadmen using straps. It is customary to provide a plurality of straps with one end of each strap connected to a deadman on one side of the tank, the other end of each strap connected to the deadman on the other side of the tank, and the straps passing over the tank such that the straps, in combination with the deadmen, prevent the tank from floating upward. Each end of a strap typically has a hook that is used to engage a loop, lug, anchor or eyebolt (xe2x80x9cfastening loopxe2x80x9d shall be used herein to refer to any of the foregoing or any other device that facilitates connection of a strap to a deadman) on the deadman. A detailed discussion of straps for use with deadmen can be found in co-pending U.S. application Ser. No. 10/135,367, filed on May 1, 2002, entitled xe2x80x9cTank Retaining System,xe2x80x9d which is commonly owned by the assignee of the present application and which is hereby incorporated by reference herein. As discussed in that application, each strap may comprise a pair of straps that are connected together by a tensioning device such as a turnbuckle, come-along, or other device. As used herein, a strap should be understood to refer to a single, continuous strap as well as a strap that is formed from two or more sections that are joined together either directly or indirectly through a tensioning or other device.
Shipping deadmen to an installation site can be expensive. USTs, especially those used for gasoline storage at service stations, are often constructed with a 10 foot diameter. On a conventional flat bed trailer, there is not enough room to place conventionally-shaped deadmen alongside a 10 foot diameter tank. This means that conventional deadmen must be shipped on a different section of the flat bed trailer from where the tank is located or that the deadmen must be shipped on a separate truck. In either situation, shipping cost is increased.
What is needed is an improved deadman that minimizes shipping costs while remaining economical and easy to use.
The present invention meets the aforementioned need to a great extent by providing a low profile deadman. In one aspect of the invention, the deadman is shaped such that it can be placed alongside a storage tank on a conventionally-sized flatbed trailer. In one preferred embodiment, the deadman includes at least one chamfered edge.